Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
The effect of concentration
19 practice questions
Practice questions
1–8 of 8 · Normal
Question 1
3 marks · Normal
Answer and see the solution →Consider the equilibrium: A sealed vessel contains 0.20 mol of X and 0.15 mol of Y at equilibrium. If 0.10 mol of Y is removed from the vessel, predict the change in the amount of X at equilibrium. Explain your answer with a calculation showing the direction of shift.
Question 2
3 marks · Normal
Answer and see the solution →In a laboratory, the following reversible reaction is at equilibrium: Explain, in terms of the effect of concentration, how the equilibrium position can be shifted to increase the amount of R(g) produced. Include why each change has this effect.
Question 3
1 mark · Normal
Answer and check →The reversible reaction is at equilibrium. What is the effect on the position of equilibrium if more N(g) is added?
- A.Shifts to the left to form more M.
- B.Shifts to the right to form more N and O.
- C.No change in the position of equilibrium.
- D.The equilibrium stops.
Question 4
2 marks · Normal
Answer and see the solution →The equation represents a reversible reaction at equilibrium. State and explain the effect on the position of equilibrium if C(g) is removed as soon as it forms.
Question 5
2 marks · Normal
Answer and see the solution →For the following equilibrium in solution: State what will happen to the position of equilibrium if more ions are added to the mixture. Explain your answer.
Question 6
4 marks · Normal
Answer and see the solution →The following reaction is at equilibrium in a closed container: A chemist adds more C to the equilibrium mixture.
(a)[1 mark]Predict the effect of adding more C on the position of equilibrium. (1)
(b)[2 marks]Explain your answer to part (a). (2)
(c)[1 mark]Suggest one way the chemist could adjust the conditions to increase the yield of D. (1)
Question 7
4 marks · Normal
Answer and see the solution →The table below shows the effect of adding reactant X to a mixture at equilibrium: X + Y \( \rightleftharpoons \) Z. Experiment [X] (mol/dm^3) added Rate of forward reaction Rate of backward reaction [Z] at equilibrium (mol) 1 — fast fast 0.70 2 0.20 faster fast 1.00 Use the data in the table to answer the questions.
(a)[1 mark]What happens to the equilibrium position when X is added? (1)
(b)[1 mark]Describe the changes in the rates of the forward and backward reactions when X is added. (1)
(c)[2 marks]Suggest an explanation for the change in the amount of Z at equilibrium. (2)
Question 8
4 marks · Normal
Answer and see the solution →The equilibrium below is present in a sealed container: A student adds more oxygen, , to the vessel.
(a)[1 mark]State the expected effect on the equilibrium position. (1)
(b)[2 marks]Explain your answer to part (a), using ideas about concentration and Le Chatelier’s principle. (2)
(c)[1 mark]What will happen to the concentration of SO3 at equilibrium? (1)